Had the most erotic encounter last weekend (out of town) with a former girlfriend with whom I can party when I feel the BDSM itch. She's in a very high-stress occupation and finds that becoming a submissive every now and then allows her to free herself and cum until she can cum no more. Our encounters usually involve her being slapped, restrained, clamps and pins on some or all parts of her body and made to cum as many times as she can take until her legs buckle and she collapses.
The other nite she asked to be hung to a pole (feet on the ground, chest to the metal pole and arms tied above her head. While I lashed her back and ass with a cat-o-nines a young lady with whom we occasionally party comforts her while massaging her clit. When the O's start they do not stop and if I stopped before she passes out I'd be in big trouble and likely not see her in this particular role again. Her final orgasm had her hanging by her hands while her friend massaged her way-too-sensitive clit roughly until she gave up one final orgasm that left a puddle on the floor. She was so damned satiated when we left that I ended up carrying her to her bed that morning.
People's mentality re why they act in a certain manner when it cums to sex or what makes them cum is just too damned fascinating.